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Category Archives: The Workbench

The hams among you know that ARRL Field Day, held the last full weekend in June, is fast approaching. A few of my ham buddies and I usually try to pack up our QRP gear and head into the forest or to the top of a local peak for a weekend of sleeping on the ground and seeing how many contacts we can scare up with just a few watts of power and a wire thrown into a tree. This year I’m trying to get a head start on preparations. I’m planning to take my four-band ElecraftK1 with internal battery pack and run off lithium AA’s for the entire weekend. My antenna’s going to be an old stand-by, a half-size G5RV hung from the highest tree I can find. My K1 has the internal ATU and it’ll tune up the G5RV with no trouble, so I’ll be able to work 40, 20, and 15 meters. I even decided to dust off my old mouse paddle–a computer mouse modified so that the left and right mouse buttons act as the dit and dah paddles (you laugh, but it works great because it’s easily managed with one hand–no need to hold it with the other hand or anchor it to something).

If you’ve read my past posts here about my antenna projects, you know that I live in a covenant-restricted neighborhood that supposedly doesn’t allow outdoor ham antennas (at least none visible from the street). Thankfully, there is no homeowners association or dues that support covenant enforcement, and none of my neighbors had thus far even mentioned the short vertical antenna I built and installed in my back yard.

Up until now, I hadn’t really given that antenna a good workout. But last weekend was Field Day, and this year I had to settle for working Field Day from the shack. Sadly, I was disappointed by my antenna’s performance. Although I managed to work 50 QSOs in four or five hours, I struggled to hear and contact other stations, even when running 100W. The noise level was very high, and signal levels were underwhelming. I worked only two SSB stations, the rest being CW contacts. It was time to rethink my antenna situation.

For a surprising number of folks, my Digital Setting Circles project is their first introduction to electronics construction techniques–mainly, the art of soldering. If you’ve never seen it done correctly, soldering can be an intimidating prospect. Someone asked me the other day whether there were any YouTube videos of someone constructing my project (none that I know of). That got me thinking–there must be plenty of “how to solder” videos around. So I checked, and sure enough, YouTube has quite a few of them.

The parasitic Lindenblad, that is. I wrote in a previous post about how I was gathering the parts to build the parasitic Lindenblad antenna for 70 cm that appeared in an article in the February 2010 QST magazine. Since then, I’ve actually managed to build one of these beasts, and for what it’s worth, it even looks like the one in the picture in the article. My first trial with it on a good pass of AO-51 was less than impressive, though. For this trial, I used my Kenwood TH-F6A connected directly to the antenna with a three-foot section of RG-8X coax (to minimize the effect of feedline losses, which can be appreciable at 70 cm). There were moments when I had good copy on the satellite, but they were few and far between. I was a little disappointed, but I wasn’t ready to give up yet. Knowing that the antenna, being more-or-less omnidirectional, didn’t have much gain (especially compared the the handheld Arrow Antenna yagi I’d been using), I wondered if a preamp might be necessary.

A few weeks ago I posted about a new Chinese ham radio satellite, and mentioned a couple of satellite antennas I was considering building. Just a few days later I found the latest QST magazine in my mailbox, complete with an article about (you guessed it) another ham radio satellite antenna project! This one, by AA2TX, describes an antenna he calls a parasitic Lindenblad (here’s a link to an AMSAT article). The antenna, for 70 cm, is right-hand-circularly polarized with an omnidirectional radiation pattern. This makes it well-suited to amateur satellite applications. I liked this design better than some of the others I was considering, so I decided to give it a whirl.

When shopping for a new car, a ham isn’t thinking about performance, color, or gas mileage. Instead, he’s asking himself, “Where can I put the ham radio?” It’s not that a ham will necessarily disqualify a car from consideration based on the ease with which a 2-meter rig can be installed. Rather, he looks at it more as an interesting engineering challenge–the more interesting, the better. After all, if it were easy, it wouldn’t be interesting, would it?

I certainly made things interesting for myself last week when I purchased a 2007 Pontiac G6 GT hardtop convertible. It’s quite a car–200-hp 3.5L V6 (not overwhelming, but adequate), power everything, heated leather seats, awesome Monsoon sound system with XM radio and a 6-CD changer–it’ll be nice and comfy for my half-hour-each-way daily commute.

A question from a builder of my Digital Setting Circles project caused me to notice a plastic enclosure that another builder had used to contain the circuit board for that project. Oscar’s web page gives a nice narrative on how he built my project, and this page shows a nice enclosure with a clear plastic top he used for the project. The box came from Jameco, and it appears to be part no. 141832. Make no mistake–you’ll have to cut holes in the sides for the serial connector, encoder connectors, and battery connector, but at least the box is about the right size and looks to be easy to work with. I’m sure there are other suitable enclosures out there, as well.

If you’ve used another enclosure and liked the results, leave a comment below and tell me about it.

A comment that I receive frequently about my Digital Setting Circles project concerns the fact that it uses a serial port rather than a USB port. I guess manufacturers don’t typically include serial ports on notebook computers or PDAs anymore. In my own defense, USB was just coming into common use when I designed this circuit about ten years ago, and USB is more complicated and expensive to implement.

I have finally seen the day when my oldest child has left the nest and gone out in the world in search of his fortune.

Okay, he’s a high school teacher, so fortune might be a bit of a stretch. Nevertheless, he’s earning his own paycheck, paying his own bills, and putting his own food on the table. One of his parting gifts from me was the title to my 1994 Ford Escort. He’d been driving it around at college for the past four years anyway, so I certainly wasn’t going to miss it, and it had been a good car.

Of course, one of the first things to eat out of his initial paychecks was–you guessed it–car repairs. His front brakes needed to be done, and he needed new tires.